A boat is travelling due east at `12ms^(-1)`. A flag on the boat flaps at `53^@N of W`. Another flag on the shore flaps due north.

Options

A. Speed of wind with respect to ground is `16ms^(-1)`
B. Speed of wind with respect to ground is `20ms^(-1)`
C. Speed of wind with respect to boat is `20ms^(-1)`
D. Speed of wind with respect to boat is `16ms^(-1)`

Answer

A, C

Explanation

a,c.
Velocity of air `= vhatj`
`vecv_(AB) = vhatj - 12hati`
`tan 53^@ = v/12 = 4/3`
`v = (4 xx12)/3 = 16ms^(-1)`
`v_(AB) = sqrt((16)^2 + (12)^2) = 20ms^(-1)` .